What Is Lomotil?
Lomotil (diphenoxylate and atropine) is a prescription (Rx) drug used to treat diarrhea in people 13 years or older. It belongs to a drug class called antidiarrheals and works by slowing the function of the bowel.
Lomotil contains two ingredients: diphenoxylate and atropine.
The body converts diphenoxylate into an active chemical called difenoxine. Difenoxine attaches to receptors on the gut wall, inhibiting peristalsis. Peristalsis is involuntary muscle contraction and relaxation. Blocking peristalsis helps reduce diarrhea.
Lomotil also contains a small amount of atropine, which can help relieve spasms. Atropine also reduces the risk of abuse since atropine in high doses can result in unpleasant side effects.
This medication is a Schedule V controlled substance. A Schedule V controlled substance means some potential for abuse (using a substance for nonmedical use), and dependence (when your body depends on the drug and you have withdrawal symptoms when you don’t take it) is possible. Lomotil contains diphenoxylate (a narcotic), which can be habit-forming.
Lomotil is available as an oral tablet and solution (liquid) formulation.
Generic Name: Diphenoxylate and atropine
Brand Name(s): Lomotil
Drug Availability: Prescription
Administration Route: Oral
Therapeutic Classification: Antidiarrheal
Available Generically: Yes
Controlled Substance: Schedule V
Active Ingredient: Diphenoxylate hydrochloride and atropine sulfate
Dosage Form(s): Tablet, liquid
What Is Lomotil Used For?
Lomotil is to help manage diarrhea in people 13 years and older. It is indicated for use as adjunctive therapy, which means in addition to other treatments. For example, a person with diarrhea may also need fluids and electrolytes in addition to their medication therapy.
Diarrhea is a common problem that can include the following symptoms:
- Stomach cramps or pain
- Fever and/or chills
- Loose stools (watery consistency)
- Nausea or vomiting
- Urgent need to have a bowel movement
How to Take Lomotil
Follow your healthcare provider's instructions for taking this medication, which should also be printed on the prescription label. Use the medication as directed, and do not take more than prescribed.
If you are taking the oral solution, use the dosing syringe that comes with the medicine, or ask your pharmacist for a measuring device. Do not use kitchen measuring devices to measure medicine because they are not as accurate. The dosage regimen for the solution is generally 10 milliliters (ml), or two regular teaspoonfuls, four times daily. For tablets, you will generally take two tablets four times a day until your symptoms have been controlled. Once you start to get better, your healthcare provider may instruct you to take a lower dose or stop the medication altogether.
Drink lots of fluids (about eight to 10 glasses of clear liquids daily) when you have diarrhea. This will help keep you from getting dehydrated. In addition, try to drink at least 1 cup, or 240 milliliters, of water every time you have a loose bowel movement. Ask your healthcare provider if you should drink an electrolyte drink like Pedialyte.
It may take up to two days before you start to feel better. Call your healthcare provider if your diarrhea does not stop after 10 days, or if you develop a fever.
Store Lomotil at room temperature (68 to 77 degrees Fahrenheit). Keep Lomotil away from heat, direct light, and moisture.
Store the tablets or solution securely in its original labeled container and out of reach of children and pets. Accidentally ingesting too much Lomotil in children or pets can result in death. Dispose of any unused medication when you are finished taking it.
How Long Does Lomotil Take to Work?
Lomotil takes effect in about one hour after a dose and reaches its maximum amount in the body in about two hours. However, it may take up to about 48 hours until your diarrhea symptoms improve. If there is no improvement within 10 days, stop taking Lomotil and call your healthcare provider.
What Are the Side Effects of Lomotil?
This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 1-800-FDA-1088.
Common Side Effects
The most common side effects of Lomotil are:
- Stomach problems such as nausea, vomiting, and pain
- Decreased appetite
- Numbness and tingling in the hands and feet
- Mood changes such as euphoria (feeling intensely happy), depression, or confusion
- Dizziness and drowsiness (do not drive until you know how Lomotil affects you)
- Red or swollen gums
- Dry mouth, nose, or throat
- Skin reactions such as hives, rash, itching
Severe Side Effects
Call your healthcare provider right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Hypersensitivity reaction or anaphylaxis: Symptoms can include rash, hives, swelling around the lips, tongue, and face, and difficulty breathing
- Respiratory depression, or a decreased ability to breathe
- Central nervous system (CNS) depression, a slowing of brain activity that can lead to decreased breathing and heart rate and loss of consciousness in severe cases
- Ileus, or when the bowels are not functioning properly
- Pancreatitis, an inflammation of the pancreas that can be serious
- Toxic megacolon, swelling and inflammation of the colon, which can be life-threatening
Long-Term Side Effects
Moderate long-term side effects of Lomotil can include constipation and depression.
Severe long-term side effects of Lomotil can include ileus, pancreatitis, or toxic megacolon (described above).
Notify your healthcare provider of any concerning side effects right away.
Report Side Effects
Lomotil may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).
Dosage: How Much Lomotil Should I Take?
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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
For severe diarrhea:
For oral dosage form (oral liquid):
- Adults—At first, the dose is 5 milligrams (mg) (2 teaspoonfuls) three or four times a day. Then, your doctor may decrease your dose to 5 mg (2 teaspoonfuls) once a day, as needed.
- Children 12 years of age or younger—Use is not recommended.
For oral dosage form (tablets):
- Adults and children 13 years of age and older—At first, the dose is 5 milligrams (mg) (2 tablets) four times a day. Then, your doctor may decrease your dose to 5 mg (2 tablets) once a day, as needed.
- Children 6 to younger than 13 years of age—Use and dose must be determined by your doctor.
- Children younger than 6 years of age—Use is not recommended.
- For oral dosage form (oral liquid):
Certain factors may affect how you take Lomotil, and in some cases, your healthcare provider may recommend a dosage adjustment.
Lomotil has not been studied in adolescents under 13, so it is unknown if it is safe and effective in this age group. Moreover, Lomotil is contraindicated in children younger than 6, meaning it should NOT be used in this population.
Because there is not enough information on Lomotil use during pregnancy, Lomotil should only be used if the benefit to the pregnant person is greater than the potential risk to the fetus. If you are pregnant or think you may be pregnant, consult your healthcare provider for medical advice.
Atropine, one of the ingredients in Lomotil, is known to be present in breast milk. The other ingredient, diphenoxylate, converts to another substance called difenoxine (diphenoxlic acid), which may be present in breast milk. The prescribing information recommends using caution with Lomotil if you are breastfeeding. Consult your healthcare provider before using Lomotil.
Lomotil should be used with caution in adults 65 and older. The Beers Criteria is a guide that lists medications that may be inappropriate for older adults. Due to its anticholinergic effects, atropine, an ingredient in Lomotil, is on the list. Anticholinergic effects include:
- Delirium (confused thinking and reduced awareness of surroundings)
- Urinary tract problems
- Dementia (loss of memory, thinking, and problem-solving skills)
- Memory problems
- Blurry vision
If you miss a dose of Lomotil, take the dose as soon as you can. But, if it is almost time for the next dose, skip the missed dose. Do not take two doses at one time.
Overdose: What Happens If I Take Too Much Lomotil?
Overdosing on Lomotil can be life-threatening.
Symptoms can include:
- Slowed breathing
- Dry skin
- Dilated pupils (larger than normal pupils) or constricted pupils (shrinking of the pupils)
- Dangerous overheating
- Fast breathing and heart rate
- Weak muscles
- Incoherent (jumbled) speech
An overdose can occur up to 30 hours after taking Lomotil. Get emergency medical help right away if you think you've taken too much Lomotil.
What Happens If I Overdose on Lomotil?
If you think you or someone else may have overdosed on Lomotil, call a healthcare provider or the Poison Control Center (800-222-1222).
If someone collapses or isn't breathing after taking Lomotil, call 911 immediately.
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It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.
Diarrhea usually stops 2 days after treatment with this medicine. If your symptoms do not improve or if they get worse within 10 days of treatment, check with your doctor.
This medicine may cause serious stomach or bowel problems (eg, toxic megacolon). This is more likely if you also have ulcerative colitis. Check with your doctor right away if you have bloating, constipation, loss of appetite, nausea, vomiting, or stomach pain.
Check with your doctor if you have dizziness, fast, shallow breathing, a fast, weak heartbeat, headache, muscle cramps, pale, clammy skin, thirst, extremely high fever or body temperature, decrease in urine volume, decrease in frequency of urination, difficulty in passing urine, painful urination, dry skin and mouth. This may be signs of condition called atropinism.
Check with your doctor before using this medicine with alcohol or other medicines that affect the central nervous system (CNS). The use of alcohol or other medicines that affect the CNS with diphenoxylate and atropine combination may worsen the side effects of this medicine, such as dizziness, poor concentration, drowsiness, unusual dreams, and trouble with sleeping. Some examples of medicines that affect the CNS are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicines, medicine for depression, medicine for anxiety, prescription pain medicine or narcotics, medicine for attention deficit and hyperactivity disorder, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.
If you think you or anyone else may have taken an overdose of this medicine, get emergency help at once. Taking an overdose of this medicine may lead to unconsciousness and possibly death. Signs or symptoms of overdose include severe drowsiness, shortness of breath or troubled breathing, fast heartbeat, and unusual warmth, dryness, and flushing of the skin.
This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
What Are Reasons I Shouldn’t Take Lomotil?
Lomotil is not appropriate for everyone. Some people should not take Lomotil.
Lomotil should not be used in:
What Other Medications Interact With Lomotil?
Lomotil has central nervous system (CNS) depressant effects. This means that it slows brain activity. Taking Lomotil with other substances or drugs that also have CNS depressant effects can cause increased side effects and can be dangerous. These include:
Lomotil is similar in structure to the opioid pain medicine Demerol (meperidine). Taking Lomotil with meperidine can cause a hypertensive crisis. A hypertensive crisis is severely high blood pressure that can lead to a stroke.
Other medications that should not be taken with Lomotil include:
Also, talk to your healthcare provider or pharmacist if you need to take any over-the-counter (OTC) cold medicine. They can help you pick one that's safe to take with Lomotil.
Other drug interactions may occur. Consult your healthcare provider or pharmacist for a full list of drug interactions.
What Medications Are Similar?
There are other medications available to treat diarrhea. Some are OTC, and some are prescription.
OTC drugs available to treat diarrhea include:
- Imodium (loperamide)
- Kaopectate (bismuth subsalicylate)
- Pepto-Bismol (bismuth subsalicylate)
Besides Lomotil, prescription drugs that treat diarrhea include:
- Viberzi (eluxadoline) treats irritable bowel syndrome with diarrhea (IBS-D)
- Xifaxan (rifaximin) treats IBS-D and traveler’s diarrhea
- Lotronex (alosetron) treats IBS-D in women who have not responded to other treatments. This medication has serious side effects that can be fatal and is used in rare cases.
- Questran (cholestyramine) is sometimes prescribed off-label for diarrhea. Off-label means that a drug is being used for an indication that is not FDA-approved.
- Bentyl (dicyclomine) or Levsin (hyoscyamine) are sometimes used to treat the muscle spasms in the stomach associated with diarrhea.
This list is a list of drugs also prescribed for diarrhea. It is NOT a list of drugs recommended to take with Lomotil. Talk to your pharmacist or a healthcare provider if you have questions.
Frequently Asked Questions
What is Lomotil used for?
Lomotil is available in oral tablet and solution form to treat diarrhea in people who are 13 years or older. Your healthcare provider may recommend Lomotil along with other measures, such as electrolyte replacement, to control your symptoms.
How does Lomotil work?
Lomotil contains diphenoxylate and atropine. When you take Lomotil orally, the body converts diphenoxylate into an active chemical called difenoxine. Difenoxine slows down involuntary muscle contractions, relieving diarrhea symptoms. There is also a small dose of atropine in Lomotil, which helps discourage overdose.
How long does it take for Lomotil to work?
You may start to feel better within two days of starting your treatment. Your healthcare provider will advise you on how long you should take your medication. If you do not feel better in 10 days, stop taking Lomotil and call your healthcare provider for further guidance.
What are the side effects of Lomotil?
Lomotil can cause side effects such as stomach problems, decrease appetite, numbness and tingling, mood changes, dizziness, sedation, lethargy, restlessness, headache, and skin reactions. Serious side effects are rare but can include severe allergic reactions. Get emergency medical help right away if you have hives, difficulty breathing, or swelling around the face.
How do I safely stop taking Lomotil?
Your healthcare provider will advise you on how long to take Lomotil. Once you feel better, you may be able to decrease the dose or stop the medicine altogether.
How Can I Stay Healthy While Taking Lomotil?
Before taking Lomotil, discuss all medical conditions and medication history with your healthcare provider. This helps ensure that Lomotil will be prescribed safely.
When taking Lomotil, follow the instructions for use. Lomotil can improve symptoms but can also cause many side effects. For this reason, taking Lomotil as directed and not more than prescribed is essential. Drink plenty of fluids, preferably water, while taking Lomotil to prevent dehydration.
Talk to your healthcare provider about other measures to treat your diarrhea. Some other ways to help you feel better include:
- Drinking eight to 10 glasses of water each day.
- Eating small meals
- Eating some salty foods, such as pretzels, and high potassium foods, like bananas and fruit juices
- Avoiding dairy, caffeine, alcohol, and carbonated drinks
While Lomotil will help relieve your symptoms, there may be an underlying cause to why you have diarrhea in the first place. For example, other medications or certain foods can cause diarrhea. Your healthcare provider will likely order blood work, a stool sample, and other necessary tests to find the reason for your symptoms.
Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.